Variable stator vanes (VSVs) are typically used in gas turbine engines to allow adjustment of the direction of airflow onto the rotating aerofoil blades e.g. in the compressor sections of the engine.
The VSVs are held radially between an outer casing of the engine and an inner shroud, the inner shroud typically being formed of metal such as aluminium or steel, or a composite material such as carbon reinforced plastics material. The shroud is normally formed as two semi-circular ring segments which are joined by fasteners.
Each VSV has a spindle at its root end and the spindles are held and pivotable (about a radial axis) within bores which are machined into the inner shroud. Each bore is lined with a polymeric bushing (e.g. formed of Vespel™) to reduce wear on the spindles and shroud and to allow for thermal expansion.
The radially innermost surface of the shroud is typically coated with an abradable liner which is abraded by rotation of a labyrinth seal located on the compressor drum to form a seal between the shroud and compressor drum.
As discussed above, known shrouds are provided with machined/drilled bores fitted with bushings. The machining of the bores and subsequent fitting of the bushing is time consuming and costly.
It is an aim of the present invention to provide a mounting arrangement for mounting a variable stator vane within a gas turbine engine which reduces manufacturing time and costs.